The problem to be addressed relates to circumstances in which the external appliance for powering requires power greater than the maximum power that can be supplied by said I/O port.
Solutions are known such as those described in U.S. Pat. No. 7,114,085 that enable demand peaks to be managed within the portable electronic appliance. That solution is appropriate when the need to exceed the maximum available power occurs intermittently. Solutions are known for powering computer peripherals that use an auxiliary power supply to add to the power available from the I/O port to which they are connected. With certain computer peripherals that require power exceeding the capacity of the port to which they are connected only infrequently, solutions involving intermediate energy storage, e.g. in supercapacitors, are commonly employed to smooth current peaks while remaining within the limits specified for the port.
Solutions in the prior art provide a partial and unsatisfactory response to the problem and they can enable power to be supplied continuously at a level greater than which can be supplied by one I/O port, only at the cost of providing an additional auxiliary power supply.
The invention seeks to make it possible to power a portable electronic appliance by at least one piece of electronic equipment that has greater capacity to supply power, said portable electronic appliance being connected to one or more other pieces of electronic equipment solely via connections to standard I/O buses.
Each of said pieces of electronic equipment may be connected to an external power supply such as an electricity mains network and/or may itself be constituted by portable equipment operating from an internal energy source.
It can be necessary to power a portable electronic appliance from an external source in order to enable it to operate continuously without drawing on its own in-built energy resources. It may also be appropriate to power the portable appliance in order to recharge its rechargeable internal power supply means, if any. It may also be appropriate to do both at once, i.e. to power the portable electronic appliance so that it provides the expected service while simultaneously charging its in-built rechargeable energy storage means, if any.